Support is requested for a Keystone Symposia meeting entitled Growth and Wasting in Heart and Skeletal Muscle, organized by Elizabeth M. McNally, Nadia A. Rosenthal and Leslie A. Leinwand. The meeting will be held in Santa Fe, New Mexico from January 26 - 31, 2014. Maintenance of cardiac and skeletal muscle mass and function is central to wellbeing in aging and illness. Striated muscles, including cardiac and skeletal muscles, increase in size and mass in response to exercise, nutritional status, pregnancy and other concomitant energy demand states. The mass of cardiac and skeletal muscle declines in response to sepsis, cancer, aging, and immobility. A confluence of metabolic and genetic factors regulates muscle mass, and both cardiac and skeletal muscle each have significant paracrine actions for growth beyond heart and muscle. The Keystone Symposia meeting on Growth and Wasting in Heart and Skeletal Muscle, which is highly unique, will highlight mechanisms and targets for both cardiac and skeletal muscle growth, emphasizing both novel pathways and new applications.